Return of Interesting article on DxO about 5D III and D800...

Started Apr 10, 2013 | Discussions
Dave Luttmann
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Re: not res
In reply to qianp2k, Apr 12, 2013

qianp2k wrote:

John Sheehy wrote:

Mako2011 wrote:

The two types of "resolution" you're speaking of...are are more related to the concept of sharpness and not resolution.

Nonsense.  Did becoming a moderator give you a license to alter reality?

LOL.  That's what I saw also he thinks himself an authority to decide who is right and who is wrong.  My puzzle on him is that why he keeps changing post subject line (title) then keeps suggesting someone off-topic

Changing subject lines has nothing to do with changing topics.

There are very few people more aware of the difference between resolution and sharpness (or acuity) than I.  I rail about the difference all the time.  I did not conflate them in my post.  It is all your doing.

He keeps downplaying sharpness (as something really not important to him) and emphasizing his "resolution".  I thought he knew what he meant until I saw this photo that closes to 100% cropped size (click 'original size' link to see in full size).  Even at reduced size, I don't see much textual details on the building and the photo is soft and mushy, and becomes total cr*b viewed at full size.  So to him 18mp is 18mp regardless if the lens can resolve or not, regardless if his eyes (or anyone's eyes) actually can resolve or not  No mention I have no idea why he shoot at ISO 250 at 1/320 from 17-55/2.8 on his 7D (from a bridge not on a moving vessel.  I know this place exactly as I was there last year).  I am sure about if I took 5Dc on the same scene with 24-105L the combo will resolve lots more fine details than his one, hehe.

And you keep confusing resolution and actance.  The 7D with good glass outresolves the 5D with good glass.  Even your shots proved it....as did those from two other people.  Your issue is that the photographic evidence doesn't support your biases...so you attempt to come up with excuses and try to invent scenerios where your old 5D can try to win....but it cant....so your rants continue.

http://www.dpreview.com/forums/post/51021107

Anyway I don't believe he knows what he is talking about, LOL.

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Just another Canon shooter
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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to schmegg, Apr 12, 2013

schmegg wrote:

I am not sure why my comment to this has disappeared.

No posts have been removed from this thread. You must be mistaken, or there is a gremlin. When did you post?

Might have been one of those cases when the site had problems, and the post would not go through.

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Dave Luttmann
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Re: not res
In reply to John Sheehy, Apr 12, 2013

John Sheehy wrote:

Mako2011 wrote:

The two types of "resolution" you're speaking of...are are more related to the concept of sharpness and not resolution.

Nonsense.  Did becoming a moderator give you a license to alter reality?

There are very few people more aware of the difference between resolution and sharpness (or acuity) than I.  I rail about the difference all the time.  I did not conflate them in my post.  It is all your doing.

then instead of railing about it you should learn the difference.  Currently, you are wrong and he is correct. You are talking about acutance...not rez

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Mako2011
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lines
In reply to aftab, Apr 12, 2013

Image resolution is the detail an image holds. Higher resolution means more image detail.

Image resolution can be measured in various ways. Basically, resolution quantifies how close lines can be to each other and still be visibly resolved.

In your scenario B example you can resolve the same number of lines in both the A and B image. The resolution is the same. The B image is softer than the A image so the sharpness of the two images differ... The resolution of the two images does not differ.

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Just another Canon shooter
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Re: lines
In reply to Mako2011, Apr 12, 2013

Mako2011 wrote:

Image resolution is the detail an image holds. Higher resolution means more image detail.

You have to explain now what "detail" is, and what it means for an image to "hold it".

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Mako2011
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In reply to Just another Canon shooter, Apr 12, 2013

Mako2011 wrote:

Image resolution is the detail an image holds. Higher resolution means more image detail.

You have to explain now what "detail" is, and what it means for an image to "hold it".

As I pointed out in this example... Number of lines. Simple stuff. You get the same count either picture.
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John Sheehy
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Re: not res
In reply to Dave Luttmann, Apr 12, 2013

Dave Luttmann wrote:

John Sheehy wrote:

Mako2011 wrote:

The two types of "resolution" you're speaking of...are are more related to the concept of sharpness and not resolution.

Nonsense.  Did becoming a moderator give you a license to alter reality?

There are very few people more aware of the difference between resolution and sharpness (or acuity) than I.  I rail about the difference all the time.  I did not conflate them in my post.  It is all your doing.

then instead of railing about it you should learn the difference.  Currently, you are wrong and he is correct. You are talking about acutance...not rez

Nonsense.  What is wrong with you two?

I never confuse resolution and acutance, or resolution and sharpness; at least in the last several years I haven't.  Maybe you guys need some remedial reading lessons?

My original post clearly said two things:

  1. Resolution can be measured relative to the frame/sensor size, or in absolute terms in the form of resolution per mm.
  2. Monolithic resolution measurements are misleading, especially with simple arrays of photosites.

I really don't you know where you come up with the idea that I confuse resolution with sharpness or acutance.

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qianp2k
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Re: not res
In reply to John Sheehy, Apr 12, 2013

John Sheehy wrote:

Dave Luttmann wrote:

John Sheehy wrote:

Mako2011 wrote:

The two types of "resolution" you're speaking of...are are more related to the concept of sharpness and not resolution.

Nonsense.  Did becoming a moderator give you a license to alter reality?

There are very few people more aware of the difference between resolution and sharpness (or acuity) than I.  I rail about the difference all the time.  I did not conflate them in my post.  It is all your doing.

then instead of railing about it you should learn the difference.  Currently, you are wrong and he is correct. You are talking about acutance...not rez

Nonsense.  What is wrong with you two?

LOL, they echo each other.

I never confuse resolution and acutance, or resolution and sharpness; at least in the last several years I haven't.  Maybe you guys need some remedial reading lessons?

My original post clearly said two things:

  1. Resolution can be measured relative to the frame/sensor size, or in absolute terms in the form of resolution per mm.
  2. Monolithic resolution measurements are misleading, especially with simple arrays of photosites.

I really don't you know where you come up with the idea that I confuse resolution with sharpness or acutance.

I am leading to believe DXOMark P-MPix Sharpness = MTF resolution (maybe average value on entire frame) + acutance (OOC default).

Nevertheless I agreed DxOMark should publish formula or at least tell us how they calculate into P-MPix number. Or DXO may think by leaving it as a mistery it will invoke controversy and therefore debates among photography world (achieved at this part), and will bring more attention to DXO (seems happening).

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John Sheehy
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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to RichRMA, Apr 12, 2013

RichRMA wrote:

If that were absolute, the Pentax Q would be the most important wildlife/astrocamera extant.

The only reason that I don't use the Q for more focal-length-limited work is because it is not easy to use it adapted to DSLR lenses, as far as subject quality is concerned, versus cropping from DSLR sensors, it trashes them.  The big pixels just can't compete, for both resolution and visible noise.

If there was an EOS camera, fully functional like the 7D but with a much smaller sensor with much smaller pixels, I'd pay $2000 for it in an instant.

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qianp2k
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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to John Sheehy, Apr 12, 2013

John Sheehy wrote:

RichRMA wrote:

If that were absolute, the Pentax Q would be the most important wildlife/astrocamera extant.

The only reason that I don't use the Q for more focal-length-limited work is because it is not easy to use it adapted to DSLR lenses, as far as subject quality is concerned, versus cropping from DSLR sensors, it trashes them.  The big pixels just can't compete, for both resolution and visible noise.

John, I know you're a huge fan of super high pixel density. This scenario only applied when you unable to move closer or you don't have long enough lenses.

If there was an EOS camera, fully functional like the 7D but with a much smaller sensor with much smaller pixels, I'd pay $2000 for it in an instant.

However in reality Pro(s) and many enthusiasts willing to spend more on super tele lenses and DSLRs in various crop formats so they don't need to crop severely. Then no way Q or any small sensor cameras can even touch Sharpness (resolution + acutance) and IQ as a whole. That's why Olympus FT DSLRs never really take off in sport fields and serious wildlife photography (except birding involved in small birds as even 800L is not long enough), no mention small-sensor Q as IQ from respective systems are not even close.

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Re: lines
In reply to Mako2011, Apr 12, 2013

Mako2011 wrote:

Mako2011 wrote:

Image resolution is the detail an image holds. Higher resolution means more image detail.

You have to explain now what "detail" is, and what it means for an image to "hold it".

As I pointed out in this example... Number of lines. Simple stuff. You get the same count either picture.

At what angle? What contrast? Which color channel? Even if you answer all that - why would that be a measure of resolution, and not of aliasing? Why not circles instead of lines? Or points?

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aftab
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Re: Same
In reply to schmegg, Apr 12, 2013

schmegg wrote:

I appreciate your posts - and I don't really disagree with most of what you say from a pragmatic standpoint.

However - I'm really not sure that it is helpful, conceptually, to attempt to espouse that resolution and sharpness are the same thing.

They are not.

Sharpness is the combination of resolution and acutance. Sharpness can vary independently of resolution. An image can be quite sharp but have low resolution (and high acutance). An image can also be soft but have high resolution (and low acutance). The best looking images have high resolution and high acutance - they appear sharp and detailed.

My personal opinion on this (as you've probably gathered as I've been pretty vocal on it - sorry) is that mixing these terms only leads to confusion down the track. You see comments like "a 5Dc out-resolves an 18MP crop" etc. These comments are made by people who are confused about these different imaging parameters - and probably because they simply have not conceptually separated and identified each for what it is (and what it is not).

I really think it's more useful to think of sharpness as what it is. And likewise resolution and acutance.

Yeah, as photographers we should keep thing simple,think of resolution as detail or discernible line pairs, line width etc over a specified area and think of sharpness as certain quality of those details. But we should also keep in mind that all these concepts are not as discrete as definitions would lead us to believe and have limitations when it comes down to final viewing of an image. That's why for many years scientists have been trying to come up with something more accurate and more practical (DXO's attempt is just one of them) for assessing optical or image quality. This is a good read

http://www.simulatedvision.co.uk/V&A_Chap10.pdf

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Mako2011
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just lines
In reply to Just another Canon shooter, Apr 13, 2013

Just another Canon shooter wrote:

Mako2011 wrote:

Mako2011 wrote:

Image resolution is the detail an image holds. Higher resolution means more image detail.

You have to explain now what "detail" is, and what it means for an image to "hold it".

As I pointed out in this example... Number of lines. Simple stuff. You get the same count either picture.

At what angle? What contrast? Which color channel? Even if you answer all that - why would that be a measure of resolution, and not of aliasing? Why not circles instead of lines? Or points?

In scenario B, as presented here, only the line count mattered as that was the only detail present. A and B were in fact the same regards resolution. Pretty obvious that angle, contrast, and color channel had no bearing on resolution in that example.

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Mako2011
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Re: not res
In reply to John Sheehy, Apr 13, 2013

John Sheehy wrote:

Dave Luttmann wrote:

John Sheehy wrote:

Mako2011 wrote:

The two types of "resolution" you're speaking of...are are more related to the concept of sharpness and not resolution.

Nonsense.  Did becoming a moderator give you a license to alter reality?

There are very few people more aware of the difference between resolution and sharpness (or acuity) than I.  I rail about the difference all the time.  I did not conflate them in my post.  It is all your doing.

then instead of railing about it you should learn the difference.  Currently, you are wrong and he is correct. You are talking about acutance...not rez

Nonsense.  What is wrong with you two?

I never confuse resolution and acutance, or resolution and sharpness; at least in the last several years I haven't.  Maybe you guys need some remedial reading lessons?

My original post clearly said two things:

  1. Resolution can be measured relative to the frame/sensor size, or in absolute terms in the form of resolution per mm.
  2. Monolithic resolution measurements are misleading, especially with simple arrays of photosites.

I really don't you know where you come up with the idea that I confuse resolution with sharpness or acutance

But you never define resolution in a way that puts everyone on the same point of reference. That leads to the same confusion DxO generates. I defined resolution above. Based on that commonly accepted definition... Is your measurement strategy in context?

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schmegg
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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to qianp2k, Apr 13, 2013

qianp2k wrote:

John Sheehy wrote:

RichRMA wrote:

If that were absolute, the Pentax Q would be the most important wildlife/astrocamera extant.

The only reason that I don't use the Q for more focal-length-limited work is because it is not easy to use it adapted to DSLR lenses, as far as subject quality is concerned, versus cropping from DSLR sensors, it trashes them.  The big pixels just can't compete, for both resolution and visible noise.

John, I know you're a huge fan of super high pixel density. This scenario only applied when you unable to move closer or you don't have long enough lenses.

Yes - and when you can move closer, it's the number of pixels - so it's still pixel density when you come down to it.

If there was an EOS camera, fully functional like the 7D but with a much smaller sensor with much smaller pixels, I'd pay $2000 for it in an instant.

However in reality Pro(s) and many enthusiasts willing to spend more on super tele lenses and DSLRs in various crop formats so they don't need to crop severely. Then no way Q or any small sensor cameras can even touch Sharpness (resolution + acutance) and IQ as a whole. That's why Olympus FT DSLRs never really take off in sport fields and serious wildlife photography (except birding involved in small birds as even 800L is not long enough), no mention small-sensor Q as IQ from respective systems are not even close.

You are missing the point. The reason is mainly because you can't get a high-performance 7D/1D style sports body in that sensor format. I agree with John that if you could, there certainly would be some who could see the benefit of being able to mount a 70-200/2.8L IS II and have 140-400/2.8L, or indeed, use a 100-400L and have a 200-800L! A body that allows this coupled with a high capability multi-point PDAF system and a high burst rate with large buffer would be extremely useful and quite competitive in certain applications. It would be easy to do 12fps with a huge buffer using a MFT sensor too!

It's not because of the sensor - it's because of the rest of the package.

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Just another Canon shooter
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Re: just lines
In reply to Mako2011, Apr 13, 2013

Mako2011 wrote:

Just another Canon shooter wrote:

Mako2011 wrote:

Mako2011 wrote:

Image resolution is the detail an image holds. Higher resolution means more image detail.

You have to explain now what "detail" is, and what it means for an image to "hold it".

As I pointed out in this example... Number of lines. Simple stuff. You get the same count either picture.

At what angle? What contrast? Which color channel? Even if you answer all that - why would that be a measure of resolution, and not of aliasing? Why not circles instead of lines? Or points?

In scenario B, as presented here, only the line count mattered as that was the only detail present. A and B were in fact the same regards resolution. Pretty obvious that angle, contrast, and color channel had no bearing on resolution in that example.

Then you have a definition of resolution which applies to one example only?

Why is the slanted edge test slanted then, if the angle has no bearing on resolution? What if you chose different spatial frequency and the other lens seem to win, etc.?

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John Sheehy
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Re: not res
In reply to Mako2011, Apr 13, 2013

Mako2011 wrote:

John Sheehy wrote:

I really don't you know where you come up with the idea that I confuse resolution with sharpness or acutance

But you never define resolution in a way that puts everyone on the same point of reference.

Yes, I did.  I said that it is trend of contrast vs frequency (either based on the frame or the mm).  That is NOT perceptual, and has nothing to do with acuity or sharpness.  It is TOTALLY empirical.

I also said that it is a mistake to choose a single contrast threshold and define resolution monolithically, based on that, and suggested that aliasing be taken into account by bifurcating the trendline, with the upper trend taking into account lucky alignment, and the lower trend unlucky alignment.

It would be much like current MTF graphs, but it would take into account the discrete sampling frequency and the resulting bifurcation, distinguishing between real resolution of frequencies sampled properly by the sampling rate, and distorted/aliased resolution caused by under-sampling.

That leads to the same confusion DxO generates. I defined resolution above. Based on that commonly accepted definition... Is your measurement strategy in context?

What leads to the same confusion?  I suggested that monolithic resolution figures based on a single contrast are insufficient for digital sensors, and explained why.  I also suggested the bifurcation of the trends, and why it is needed.

The only time I have introduced perception was to explain why these things are needed to avoid being fooled by perception, such as when people are impressed by the acuity of 100% pixel views, ignoring the fact that this means bad sampling, and tells nothing directly about the maximum usable resolution of the image.

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John Sheehy
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Re: just lines
In reply to Mako2011, Apr 13, 2013

Mako2011 wrote:

In scenario B, as presented here, only the line count mattered as that was the only detail present. A and B were in fact the same regards resolution. Pretty obvious that angle, contrast, and color channel had no bearing on resolution in that example.

The limit to resolution at visible contrast levels in these samples is the sampling rate; IOW, the same maximum resolution, but at different contrast levels.  Things are quite different when the optics are over-sampled for usable contrast levels.  Then, resolution is limited in a practical sense by usable contrast in the face of noise.

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John Sheehy
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Re: just lines
In reply to Just another Canon shooter, Apr 13, 2013

Just another Canon shooter wrote:

Why is the slanted edge test slanted then, if the angle has no bearing on resolution? What if you chose different spatial frequency and the other lens seem to win, etc.?

Of course, if the optics are properly sampled, the only difference in angular results are those imposed by the optics, and no appreciable difference is imposed by the discrete sampling structure.

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Earthlight
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John, your take on the latest Canons
In reply to John Sheehy, Apr 13, 2013

Have you had the chance to see whether anything has changed in the latest 18 MP sensors in terms of pattern noise?

thanks!

Earthlight

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